Flies were swarming throughout the shop as temperatures raced into the upper nineties. Forty-pound wheels of cheese sat behind the glass and under the counter, extracting whatever cool air they could from the refrigerated enclosure. We ordered a half pound of the comté cheese, which was being strangled by a several inch-thick rind. The cheese monger gestured to us that it was edible, and in response to our surprise, he cut off a large piece, popped it in his mouth, and after minimal chewing, swallowed it whole. We spoke little French and he spoke no English, but we were instantly united in our mutual love of cheese. He showed us several pictures of Eastern France, where the unpasteurized cow's milk was converted to cheese during its storage in the caves below the Franche-Comté region. However, as he was handing us the wrapped cheese, we spotted the cured duck links hanging from the ceiling. Below them was a sign with several words, one of which was saucisson. He pointed and said "canard." With little to no French vocabulary, I knew what canard meant. Throughout the trip, I had eaten duck every day, for nine straight days. I had never had cured duck before, and after trying it later that night, I realized I had been missing out for the first 36 years of my life.

Rewinding several years before my epicurean awakening blessed by duck prosciutto, the issues of processed meat were thrust into the spotlight when the IARC at the World Health Organization classified processed meat as a Group 1 carcinogen to humans, citing data linking it to colorectal cancer. While red meat has taken a beating for years, it pales in comparison to the beat-down given to processed meats, including cured meats, hot dogs, sausage, pickled meats, and beef jerky, to name a few. But are all processed meats the same? Should I feel guilty for the immense enjoyment I received from the duck prosciutto?

The History of Cured Meat

Processed meat is a broad category that includes any meats that are manipulated through a "process" to increase their shelf-life or flavor. Curing meat is the process of adding salt to preserve meat, especially when it is unable to be refrigerated or frozen, or in other words, any time before the mid 1750's (when refrigeration started, though this was reserved for the uber-wealthy and only in the 1900's did us common folk have household devices).

While many internet and news sources would lead us to believe that the process of curing meat began only recently and was perfected by Oscar Meyer, this could not be any further from the real history of meat preservation. Processing meat and fish through salting and drying techniques was first recorded in Egypt around 3,500 BC. The Chinese documented using salt to cure meat about 2,000 years later, and the Greeks followed around 200-300 BC.

Like most things, the Greeks' recipe eventually made its way to the Romans, and one of the oldest recorded known recipes for cured meat is from the senator and philosopher Cato the Elder. The recipe was basically a set of directions to add salt, let the meat sit, remove the salt, and then hang the cured meats to dry. The Greeks also made salsamentum, which is salted fat. The curing was not limited to meats, as they also mixed fermented fish with olive oil and wine to make œnogaros. Even the Native Americans were in on the action and salted their meats, as documented by the Jamestown settlement in Virginia. In other words, curing meat has been a long and integral part of our history and culture across the globe.

Curing mainly involves the addition of salt to the meat, poultry, or fish to extract water, dehydrate the meat, and kill harmful bacteria. Spices can be added, and some sources are cooked or smoked as part of the process. This cultural form of meat preservation was prized for thousands of years, until the industrialization of the process in the 18th century began to trade quality for mass production and profits. Once again, big business uprooted a traditional process to maximize quantity. Critics of the movement, like Upton Sinclair in his expose The Jungle, exposed the issues that the mass production of meat processing was creating, and many of these issues still exist today, which we will turn our attention to below.

Regardless of the current controversies of cured meats, they remain a familial tradition and heritage of cultures around the world, from Spain to China and everywhere between. Places like Parma in Italy, famous for Parma ham and parmesan cheese, still use salt and the same ancient technique from centuries ago when sailors carried salt from the Adriatic Sea and, combined with Parma's dry winds, locals used it to cure their meat. My family continues to make soppressata from a time-honored recipe, and we look forward to eating it on various occasions throughout the year, but especially on Christmas Eve to accompany the Seven Fishes.

The Problem with Processed Meats

Few foods with actual nutritional value seem to get as bad a rap as processed meat these days. They are lumped in with harmful chemicals and carcinogens according to the IARC report. Manyepidemiologic studies- the studies that follow a population to estimate what dietary habits may be associated with cancer - reveal a concerning association between an increased risk of cancer and processed meat consumption. Many of these studies, however, are less than stellar in their methods, and others reveal such a small risk that it is difficult to take them seriously (and many people do not). For instance, a study associating processed meat consumption with pancreatic cancer made a splash on the nightly news and many media sources. What the study actually showed was that those individuals who ate more processed meats experienced a higher risk of pancreatic cancer than the normal population, an increase from 1.4% to 1.58%. Besides the many other issues with the study, with minuscule conclusions like this, it is hard to take these studies seriously.

Furthermore, many point to the mislabeled villain - salt - in cured meats as the major health issue. I wrote an article back in 2012 on the issues with dietary recommendations against salt intake and discussed the unhealthy issues with salt restriction at length in my book Misguided Medicine. These concerns with cured meat are vastly overblown and oftentimes bluntly wrong, especially for those engaging in a healthy diet and lifestyle.

Comment: The case against salt is, and always has been, misguided in the extreme. See:

Despite all these inconsistencies, there are realistic concerns with processed meat in our diet. For instance, deli meat often contains a laundry list of preservatives and chemicals, like:

Citric Acid

Corn Syrup

BHT, BHA, & Tocopherols

Gelatin

Modified Food Starch

Monosodium Glutamate (MSG)

Sodium Nitrite

Soy Protein

Sodium Phosphate

Yeast

Sodium Diacetate

Sodium Erythorbate

Sugar

Dextrose

Carrageenan

Furthermore, while epidemiologic studies only provide us with associations and theories to study further, they do seem to show a consistent, albeit small, issue with processed meats.

Botulism and the Nitrate Conspiracy

While meats have been cured in unsanitary caves and basements of old Italian men, like my great-grandfather, for thousands of years, one bacteria has still found a way to elude us. Adding salt to pull moisture out of the meat and hanging it with weights to facilitate this process works well to remove harmful bacteria. However, botulism can still occur in rare cases.

Though botulism outbreaks are rare - there were 160 outbreaks in the US, affecting 263 people in the decade between 1990 and 2000 - the consequences can be devastating. The all-too-familiar expressionless and creepy paralyzed faces of botox-addicted celebrities comes from botulism, but this paralysis can be fatal when occurring throughout the body. Twelve to 36 hours after consuming food containing botulism, victims notice difficulty speaking, swallowing, and eventually, breathing. As a result, victims are given an antitoxin, but may require mechanical ventilation with a respirator to survive. In other words botulism is best avoided.

The connection between botulism and processed meats became well-known during the 1700's, when sausages in Germany led to numerous outbreaks of a mysterious disease that took the lives of several people. A locally-produced blood sausage appeared to be the culprit, and 230 cases were linked to it (no pun intended), leading its discoverer to name it "sausage poison." Eventually it was called botulism, after the Latin word "botulus," which meant sausage.

The actual bacteria Clostridium botulinum was not discovered until almost a century later in the late 1800's at the University of Ghent after an outbreak from smoked ham occurred in Belgium. At that point, it was discovered that the botulin toxin produced by the bacteria caused potentially fatal paralysis of the muscles that control our movement and breathing. Only much later did we realize we could inject this into certain areas to "paralyze" wrinkles.

Clostridium bacteria thrive in a moist and nonacidic environment lacking oxygen. While traditional meat curing requires salt and a physical environment to remove all moisture to offset this risk, things can often go unplanned. This also makes hams and lunch meats prime targets for Clostridium since they are purposefully filled with water to plump them up. Additionally, smoking meat helps Clostridium by removing the air (and oxygen) and keeping it at a temperature where it thrives. Much like the smoked ham in Belgium in 1895, adding water to meat and then smoking it may be the perfect recipe for botulism. Improperly cooked foods are also a breeding ground for Clostridium.

The Solution?

There are two options to avoid botulism:

Cure your meats with the utmost of precision with salt alone

Simply add nitrates

Whereas option #1 may still result in a rare case of food poisoning, option #2 seems to bring that risk close to zero, leading to the widespread use of nitrates. Salt must be added to the meat to extract moisture, dehydrate the meat, and kill off harmful bacteria. When done appropriately, it should eliminate the risk of botulism. Yet, while the risk of botulism is low, its risk of massive complications has ushered in the widespread use of nitrates.

However, recently the term nitrate has become a scary one since it takes the blame for most of the health issues of processed meats. Many studies seem to forget that most meats, like deli meats and hotdogs, are usually consumed with a bun (often white bread) and washed down with bubbly sugar water known as soda. Yet, nitrates still get the lion's share of the blame.

It is not clear when nitrates were first used, but the Romans noticed reddening of meats that were cured with certain salts, and this was eventually attributed to the nitrates. When nitrates are added to meat, they react with the bacteria present, creating nitrites. Nitrites do the bulk of work during the curing process and are eventually converted to nitric oxide. The nitrite then reacts with myoglobin, which are the muscle cells found in the lean part of the meat, giving it a deeper red color. Nitrate usage involves a longer process, which is why it is commonly employed for longer cured meats, like soppressata.

Nowadays, nitrites are generally used to bypass the conversion from nitrates. Other agents are added as well to speeds things up, like erythorbic acid (an isomer of vitamin C) and ascorbic acid (vitamin C), which increases the conversion to nitric oxide. These chemicals also react with the myoglobin, creating a reddish/pinkish color from the chemical nitrosomyoglobin.

This brings up a key point: nitrites require the lean muscle meat to form this reaction. Therefore, only salt is generally used for fatty portions, and this explains why certain prosciutto is preserved through salting alone. For instance, prosciutto from San Daniele contains only pork and sea salt, and prosciutto carrying the label "Protected Designation of Origin" only uses salt.

There is more to the story with nitrites. When they react with amines in these meats (amines are nitrogen-containing compounds), they can form nitrosamines. These are similar, but not identical to heterocyclic amines (HCAs) formed from the charring, burning, and high-heat cooking of meat that can be minimized with the use of marinades, consumption of anticancer vegetables, and of course by avoiding high heat and flames. Nitrosamines and HCAs are often confused, since both occur during a chemical reaction with lean muscle meat. HCAs are formed by the reaction of amino acids from the muscle meat, catalyzed by the high cooking heat, with sugar and creatine within the meat. Simply burning meat can create HCAs. Nitrosamines, on the other hand, are formed from the reaction of nitrite and amines (from protein).

These substances have been shown to increase cancer in rodents. While certainly concerning, the rodents in these studies were given massive amounts that are nearly impossible to achieve through eating cured or charred meats. Both substances are dangerous after they are activated by certain mechanisms within the body, likephase I detoxification. This point is extremely important, as a healthy functioning phase II detoxification system should quickly offset the potential damage from these substances.

This is where the confusion starts for most health experts that recommend avoiding all cured meats due to their cancer-causing nitrosamines. Nitrosamines are formed when nitrites react with the amines from the meat protein during cooking at high temperatures, much like with HCAs. However, similar to a grill, another gastronomic chamber that can facilitate this reaction is the stomach. The acidic environment within the stomach turns nitrites into nitrous acid, which eventually reacts with an amine to form nitrosamine. The whole process is similar to the formation of HCAs with some key differences:

The reaction occurs in our stomach

Our saliva is a large source of nitrites1

Vegetables are the largest source of nitrates within the diet

Nitrites react with proteins (not fat) in lean meat to make nitrosamines

We have been recommended to eat lean meats as opposed to fatty sources for several decades

These same recommendations come from sources that shun cured meats

Confused? You are not alone, because little of the science as to why cured meats may be unhealthy, cause cancer, and are associated with an increased risk of pancreatic cancer from 1.4 to 1.58% is compatible with other dietary recommendations. Further underscoring the confusion, even the American Medical Association had made a statement that nitrates and cured meats are safe and not associated with cancer risk. They have since pulled this from their website. The internet is now littered with websites and medical documents that both praise and chastise the health impact of nitrates, of course depending on the source. Some scientists and medical researchers have even claimed that the benefit of vegetables may be from their nitrate components, as these compounds dilate our blood vessels and lower our blood pressure.2It seems most prudent to continue eatingvegetables,spices, and foods that help increase our bodies' detoxification mechanisms to break down and eliminate any nitrosamines. Many of these same foods help feed and support bowel bacteria that help to metabolize nitrosamines.3

Nitrates are also converted to nitrites by bacteria, including our natural oral bacteria4 and gut bacteria.5 What this means is that other sources of nitrates (and of course nitrites) would be concerning if nitrites are the root of the problem. Well, the largest source of dietary nitrates are vegetables, and these values are much larger than processed meats. Furthermore, nitrates are present in our drinking water. If the proteins from meat are the major concern, it would seem less of an issue of whether nitrates are used in the process of curing the meat.

Combining all of these facts makes it unsurprising that the majority of nitrates that we are exposed to are produced within our body.6 Some think this may not be such a bad thing, as nitrites can turn into nitric oxide, which dilates our blood vessels and has several health benefits. Some even endorse nitrates as a major benefit of vegetable consumption, as their conversion to nitric oxide dilates our blood vessels and lowers our blood pressure.2

Many "nitrate-free" sources of bacon and cured meat often replace the nitrates with celery salt. They often command a higher price. Celery salt contains ample amounts of nitrates, so keep this in mind the next time you encounter this false advertising.

More recently, vitamin C and its precursor, erythorbic acid, have been added to the curing process. This is important for meats with nitrates/nitrites that may be exposed to high heat cooking. These compounds hasten the process of nitrates interacting with the meat, leaving minimal amounts of nitrites left to cause a reaction during cooking. This is one reason why many believe that the nitrates in plants are not converted to nitrosamines. This same logic also provides an easy fix if nitrosamines are indeed the issue with cured meats - eat them with some vegetables or foods that contain antioxidants.

Avoiding the usage of nitrites or celery salt (which contains nitrates) in meats that will eventually be cooked is an easy way to avoid these nitrosamines.

The elephant in the room that accompanies every discussion of the population studies associating processed meats and cancer are the accompanying foods. With prosciutto and soppressata, I usually include a nice glass of red wine, some cheese, and a couple vegetables. With hamburgers and hot dogs, most people usually consume bread or a bun, fries cooked in low-quality vegetable oils, and a sugary soda.

So, if you believe the epidemiologic studies and really want to play it safe, avoid all processed meats. If you are less concerned, enjoy process meats, are happy eating them as a low-carbohydrate snack, and think it is reasonable to at least consume some processed meats, stick to my rules:

Like most things, the less ingredients the better: If you can't pronounce it, don't eat it

Avoid smoked meats: The jury is still out on nitrates, but there are enough options that we can play it safe by avoiding smoked meats

Avoid lunch meats and other sources made from meats that lack quality: Like all sources of pork, go for pastured pork; Like all beef, go for 100% grass-fed; And if you can find and eat duck "sausage," the most delicious sausage in the world, make sure it is from pastured ducks

Eat meats that your Uncle Mark and Frank would create and hang to dry in the basement: Prosciutto and soppressata, like most demonized foods, are actually part of my cultural heritage and I especially love enjoying them on the holidays with my family and a nice glass of red wine; Cured meats, like nearly all foods, follow the adage if you want to make sure it's the best quality, do it yourself (or at least have another family member or friend do it). You can add some spices and keep the processing part to salt, which will kill bacteria and cure the meat, but of course keep it safe

Comment: The warning against smoked meats seems overly cautious. Smoking is another tradition that goes back thousands of years. Since our ancient ancestors started cooking food, we've been getting smoke with our meat. Plus, who wants to avoid bacon?

Conclusions

As discussed here and here, with an optimized detoxification system, supported by spices, vegetables, maybe even some wine, and bitter foods, the damage, if any, from eating cured meats remains unknown. Whether any issues accompany eating small amounts of cured meats or consuming them with detoxification-supporting vegetables is even less clear.

Will eating cured meat kill you? No more than a piece of birthday cake at your aunt Mable's 90th birthday party. The difference, of course, is that the cured meat actually provides nutritional value, does not turn your blood sugar into a roller coaster of despair, and does not cause you to crave more food afterwards. If we viewed foods like cultural cured meats as a nice treat instead of sugary sweets, rates of obesity would likely be much lower.

The verdict is still out on a culturally-rich food that has been around for thousands of years. When eaten in moderation and reasonable amounts, the evidence that these traditionally processed foods will cause cancer is lacking. Furthermore, even in worst-case scenarios, the risk is small, varies widely between studies, and does not incorporate those other healthy lifestyle activities that offset the potential negative aspects of many foods.

Cured Meats References:

Mirvish, S. S. et al. Nitrate and nitrite concentrations in human saliva for men and women at different ages and times of the day and their consistency over time. Eur. J. Cancer Prev.9, 335-42 (2000).